Rotation mechanism for rock drills



Jan. 12, 1943. F. SLATER 2,307,865

ROTATION MECHANISM FOR ROCK DRILLS Filed Sept. 17. 1941 INVEN'I OR .FveoTM 551222912.

HIS ATTORNEY.

Patented Jan. 12, 1943 2,307,865 ROTATION MECHANISM FOR ROCK DRILLS Fred M. Slater, Phillipsburg, N. Ingersoil-Rand Company, New

J., assignor to York, N. Y., a

corporation of New Jersey Application September 17, 1941, Serial No. 411,127

' 1 Claim. (Cl. 121-7) This invention relates to rock drills, and more particularly to a rotation mechanism for rock drills of the fluid actuated hammer type.

One object of the invention is to equip the rock drill with a powerful and compact rotation mechanism and to protect the rotation against shock incident to the operation of the percussive element of the rock drill.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing accompanying this specification and in which similar reference numerals refer to similar parts,

Figure 1 is a longitudinal elevation, partly in section, of the front end of a rock drill equipped with a rotation mechanism constructed in accordance with the practice of the invention,

Figure 2 is a transverse view taken through Figure 1 n the line 2-2,

Figure 3 is a transverse view taken through Figure 2 on the line 3-3, and

Figure 4 is a transverse view Figure 3 on the line 4-4.

Referring more particularly to the drawing, 20 designates, in general, the front end of a rock drill and 2i a working implement extending into the rock drill to be actuated thereby.

taken through The rock drill comprises, as casing parts, a

cylinder 22 and a front head 23 which is centralized with respect to the cylinder 22 by a front cylinder washer 24 having extensions 25 and 23 extending respectively into the opposed ends of the front head and the cylinder.

The front cylinder washer 24 and its extensions are hollow, having a bore 21 to receive slidably the stem 28 of a hammer piston 29 reciprocable in the cylinder 22. The front end of the bore 21 is enlarged somewhat to form a cavity 30 into which the shank end of the working implement 2| extends to receive the blows of the hammer piston.

The front end of the extension 25 of the front cylinder washer serves as an abutment for a rotary chuck 31 in the front head 23 containing a sleeve 32 having a hexagonal bore 33 wherewith the shank of the working implement 2| is slidably interlocked.

The rotation mechanism constructed in accordance with the practice of the invention and serving to impart rotary movement to the chuck 3! for shifting the working implement between blows of the hammer piston 29 is arranged on the front head 23. The front head is accordingly provided with an enlargement 34 that extends transversely of the front head near the rearward end thereof. Within the enlargement 34 is a bore 3'5 that extends entirely through and endwise of the enlargement to receive a driver 38 .shown as being in the form of a worm 31 that meshes with a worm wheel 33 on the periphery of the chuck -3l The ends of the bore are in the form of enlarged recesses 39 having their outer ends sealed by covers 40 that are 34 by bolts 4 I. containers for In effect, the recesses 39 serve as motors serving to rotate the worm 31. In each recess is a bushing 42 that abuts at one end the cover 40 and at its other end a plate 43 arranged in the bottom of the recess 33. The interior of each bushing 42 constitutes a chamber 44 for a rotor 48 that is inserted into and removed from the recess through the outer end of the recess and is arranged eccentrically within the chamber 44, Each rotor has a series of slots 46 for the accommodation of vanes 41 arranged slidably therein to seat with their outer ends against the bushing 42.

Each rotor is provided with an axial hole 48 to receive slidably one of a pair of cylindrical extensions or reduced shaft portions 43 forming continuations of the ends of the worm 31. The extensions 43 are held against rotary movement with respect to the rotors by keys 53 inserted in the extensions and extending slidably into key slots 5| in the axial holes 48. The free ends of the extensions 43 extend loosely into cavities 52 in the inner surfaces of the covers 43 and are free to move longitudinally within the cavities without hindrance by the covers whenever the worm 31 is shifted endwise with respect to the rotors 45.

In the form of the invention shown each extension 49 is provided with an anti-friction bearing 53 the outer race of which is seated in an annular groove 54 in the bore 35 directly adjacent a plate 43 which serves as n abutment for the bearing.

In order to normally hold the worm 31 in a position substantially midway between the rotors 45 and thus in a correct operativeposition with respect to the worm wheel 38 and also to cushion endwise movement of the worm, a spring 54 is disposed about each extension 43 to seat at one end against an end of the worm 31 and at its other end against the inner race of the adjacent bearing 53. Thus, in the operation of the rotation mechanism, whenever shock induced by the percussive element of the rock drill, or by the working implement, is imparted to the worm '31 so that it' will be moved endwise the springs 45 secured to the enlargement will act to again'quickly restore the worm to its normal operating position.

The pressure fluid serving to drive the rotors I5 is conveyed thereto by a supply passage 58 in the casing having branch passages 51 that lead to supply chambers 58 in the enlargement 3| and in the transverse planes of the plates 43. The chambers 58 lie directly adjacent the rotor chambars 44 and communicate therewith through passages 59 for supplying motive fluid to the rotors.

Each chamber 44, as is customary, is provided with an exhaust passage 80, or passages, for conveying the motive fluid from the chambers 44 and in the present instance the exhaust passages open into the cavity GI containing the worm gear 38 and the worm 31 so that the lubricant entrained in the exhaust fluid will be deposited on the coopand without imparting endwise thrust to the rotors. The shock thus applied to the worm will, moreover, be absorbed by the springs which are at all times slightly compressed and will, therefore, constantly tend to again restore the worm to a position midway between the bearings 53 and thus to the correct operative position with respect to the worm wheel 38.

I claim:

In a rock drill, the combination of a casing having a gear chamber and a chuck rotatable in the casing having a worm gear in the gear chamber, said casing having a transverse bore and enlarged recesses at the ends of the bore, covers for the outer ends of the recesses, rotors in the recesses having holes extending axially therethrough, said rotors being insertable into and removable from the recesses through the outer ends of said recesses, slidable vanes in the rotors, means for supplying pressure fluid to the recesses to drive the rotors, there being exhaust ports in the casing for the recesses, a worm in the bore to engage the worm gear, shaft portions on the worm extending slidably into the holes, hearings in the bore for the shaft portions, and springs on the shaft portions interposed between the worm and the bearings 'to yieldingly resist the thrust of the worm and the shaft portions in the direction of the rotors.

FRED M. SLATER. 

